Quote from: NeuroticFish on Today at 07:42:51 AM

Quote from: ViceOfBTC21 on December 16, 2020, 10:11:38 PM

I think that since the PDAs (Personal Digital Assistants) aren't dedicated to cryptocurrencies but rather using them as a pocket computer, it would be therefore more secure. I don't really understand security through, so correct me if I'm wrong.

The usual security issues a cold storage faces is in the process of transferring the unsigned transaction to the cold storage and then the signed transaction back to the live device.
I don't expect the PDA will have a nice and simple QR based implementation like it would be possible with modern devices, hence bad surprises can occur at the transfer of those files (which I also expect to be rather clumsy, hence it will lose all its friendliness compared to HWs). Keep in mind that information has to be sent in both directions for signing.

But maybe I am missing something too...

I guess that we did some hard work, it should be possible to develop a one-way cold wallet that doesn't need to communicate with the crypto spending file. Even the Coldcard, which says that it's truly airgapped, requires you to use SD card from your computer. So if you are ultra-paranoid, you might decide to spend all at once and replace your Coldcard every time.

As Palm OS PDAs are touchscreen-based, it is possible to develop a companion app for current Android/iOS smartphones and Windows/Mac/Linux computers that will guide you with the progress of entering information on PDA by hand. If you don't want to enter everything by hand with Graffiti, you can use a keyboard, camera (QR) or audio modem (speaker and microphone) modules. The last feature is in Electrum, so implementing it probably wouldn't be a problem, but how you will input/output the sound? Again, modules are the answer, but there are no commercial modules such as this available and we need to hack one at home.

This is not impossible, as there have been external keyboards and camera module produced for Palm PDAs. That's for über-paranoid people and I don't need this kind of security, so it can communicate with computer through serial or IrDA. Again, I was speaking about air-gapped security, but the user should be able to use the program wired or this paranoid way if they want to.

The problem is how to get the signed transaction out of PDA. Again, serial or IrDA can be used. But again what the person is extremely paranoid again? We have a screen, so the user can either retype the user-friendly text back to the computer (as long as it's not too long) or display a scannable QR code with a transaction ready to be sent to the Bitcoin network.

Quote from: NeuroticFish on Today at 07:42:51 AM

Quote from: ViceOfBTC21 on December 16, 2020, 10:11:38 PM

An old PDA lying somewhere is much less suspicious than a hardware wallet.

I agree to this.
Still, I always tell that's safer to keep on hardware wallet only the funds you expect to use in the rather near future while the HODL funds can stay nicely on any variation of paper wallet/seed/steel/whatever.

Hardware wallets are also pretty secure for cold storage of low amounts of cryptocurrency (below $10000), but it is also possible to split your HODLings between hardware wallets so the compromise of one would keep at least remaining hardware wallets secure. Anyway, don't keep more crypto in hot wallets than you would carry in your real-life wallet. Bitcoin is electronic cash, not a bank, so treat it as such.

Quote from: NeuroticFish on Today at 07:42:51 AM

And imho this security+convenience mix can render the PDA useless.

Of course I said that the program can lock you out of the rest of the OS unless you explicitly exit an app (preferably with explicit warning to avoid using it pseudo-hardware wallet as your PDA). Palm OS, while primitive in today's standards, is much more flexible than currently existing mobile operating systems as it doesn't have sandboxing, permissions, etc. You can do everything you want straight out-of-the-box and we can use it to our advantage.

Sometimes the more secure option is a more convenient one, but not always. For example graphical PGP overlays and e-mail plugins can be safer than their command line counterparts as you don't need to save decrypted files on your hard drive. If your computer is compromised, you're fucked anyway.